Improved metal for and mode of manufacturing car-wheels



QFEICE.

P l i i E WILLIAM G. HAMILTON, OF NEW'YORK, N. Y.

IMPROVED METAL FOR AND MODE OF MANUFACTURING CAR-WHEELS.

Specification forming part of Letters Patent No. 85,089, dated December22, 1868.

To all whom it may concern:

Be it known that I, WILLIAM G. HAMILTON,

I of the city, county, and State of New York, have invented a new anduseful Improvement in Car- Wheels; and I do hereby declare that the.following is a full, clear, and'exact description thereof, whichwillenable others skilled in the art to make and use the same.

Thebest ear-wheels at present made are composed of cast-iron withchilled treads; but such wheels are necessarily lacking in tensilestrength, and their breakage is one of the most frequent causes ofdisaster to life and property upon all railroads. The only metal thatseems to possess suiiicient tensile strength to resist the severe.concussions to. which car-wheels are exposed is cast steel, and, to someextent, this material has been employed in their manufacture; but,.owingto the high temperature requisite to cast this metal, it

is impossible to chill the treads of such wheels, as the molds wouldbecome melted,--and the result is that the-treads of steel wheels soonwear out and become uneven and worthless. The objectof this improvementis to produceacar-wheel which shall have, to a great extent, the tensilestrength of steel throughout its body, coupled with the hardness ofchilled iron at the tread.

I have found, by experiment, that a mixture of steel, low steel, orsteel-sponge, made direct from the ore, and cast-iron, preferably ofabout equal parts, but which may be changed according to circumstances,produces, when melted, either together or separately, and mixed in amolten state, a compound which, when cast in chill-molds in the ordinarymanner for producing cast-iron wheels, will chill in the tread andform asmooth homogeneous casting, having. the quality of re- 'sistanee totensile strain in a higher degree than any compound of metal heretoforeknown,-which can be cast at a temperature sufficiently low to chill.This result is produced, as I suppose, by the partial decarbonization ofthe iron on the one hand by the admixture of the steel-therewith and 'onthe other, by the maintenance of the steel by the iron' in a fluidcondition, sufficiently low, in

respect to temperature, to cast in chill-molds.

By the use of this improvement I am enabled to produce, in a convenientmanner, by'the use of the ordinary molds, a car-wheel having a.ten-'sile strength approaching that of cast-steel, with a durabilityandhardness of. tread equal, for all practical purposes, to that of thebest chilled cast iron wheels. I e

I do not limit or confine myself to any particular method ofmanipulation but I prefer to make use of the ordinary molds andprocesses employed in the production of cast-iron wheels. 7

Having thus described my invention, I claim as new, and desire to secureby Letters Patent, as an improved article .of' manufacture- Acarwheelcomposed of mixed steel, low steel, or steel-spon ge, and cast-ironmtith chilled tread, substantially as described.

' WM. G; HAMILTON.

Witnesses:

A. E. BEACH, FRANK BLooKLEY.

